1. Field of the Invention
This invention relates to valves, and more particularly to a valve and apparatus for sampling and measuring the pressure of spinal fluid.
2. Description of the Prior Art
Instruments for measuring spinal fluid pressure are known, such as disclosed in Reiss et al U.S. Pat. No. 3,526,218, which shows a three-way stopcock for selectively taking fluid pressures and samples. However, such devices require a series of manipulations of the stopcock in order to measure the pressure and obtain samples, and have preassigned ports through which pressure measurements and samples are taken due to the required manipulations.
Also, in the prior art valves, a sample of spinal fluid is obtained by positioning a receptacle below the valve and allowing the fluid to drip or flow into the receptacle. Consequently, the fluid sample is exposed to the air while passing from the valve into the receptacle, and the sample may become contaminated during collection, which is undesirable, or may miss the receptacle and be lost.
In the past, after a pressure measurement has been taken, it has been necessary in such devices to retain a pressure measuring instrument, such as a manometer, on the device while fluid samples are being taken. However, this requirement is undesirable since the manometer causes inconvenience during completion of the sampling procedure due to its bulk and adds weight to a needle in the device which has been inserted into the spine.
Valves for catheter retention balloons are disclosed in Gould et al U.S. Pat No. 3,399,677, Harautuneian 3,385,301, Swanson U.S. Pat. No. 3,409,015, and Garth U.S. Pat. No. 3,087,492.